Japan navy admits 'losing' $5 million submarine

Japan has admitted that its navy lost a $5 million (£3 million) unmanned submarine during a survey last year, with a nine-day search of the ocean floor yielding nothing.

The Maritime Self-Defence Force was using the remote-controlled submersible in the Tsugaru Strait between Japan's main island of Honshu and its northern land mass, Hokkaido, in November, a defence ministry official said.

"The vehicle was being used to survey the underwater terrain as well as water currents and temperatures," he told AFP.

The unmanned craft, which is three metres (10 feet) long and two metres wide, and weighs about five tons, disappeared after the cable that connected it to a surface ship was severed.

Mariners searched the ocean floor in the area for the following nine days, but to no avail, the official said.